\section{Glossary}

\begin{description}

\item [date] \label{glos:date} A date is used to specify an instant of time at the Greenwich meridian.  It consists
of year, month, day of month and time of day components.

\item [time] \label{glos:time} A time is used to specify an interval of time. 
              
\item [calendar day] \label{glos:calendarday} The day number in the calendar year. January 1 is calendar day 1. 
Calendar day expressed in 
a floating point format is used to express the day number plus the time of day at Greenwich. For example, assuming a Gregorian calendar: 

\begin{tabular}{ll}
{\bf date}              & {\bf calendar day} \\
\hline 
10 January 2000, 6Z     & 10.25 \\
31 December 2000, 18Z   & 366.75 
\end{tabular}

\item [no-leap calendar] \label{glos:noleap} Every year uses the same months and days per month as in a non-leap 
year of a Gregorian calendar.

\end{description}











